Engine starting gearing

ABSTRACT

Starter gearing of the positive shift dentil type overrunning clutch is shown herein. In order to provide maximum service life with a minimum of wear the drive is provided with means forming a low friction substantially axially solid connection between the pinion and the starter gearing sleeve which interconnects the starter gearing with the rotary power shaft.

United States Patent Digby [451 Feb. 6, 1973 [5 ENGINE STARTING GEARING 3,263,509 8/1966 Digby ..74/6 Inventor: James L g y Elmira N-Yl 3,318,162 5/1967 Sabanm ..74/6

[73] Assignee: The Bendix Corporation Primary Examiner-C. J. Husar Attorne Robert A. Benzi er and Plante Hartz 22 F1 d: M n12 1971 Y g i 1 1 e are Smith & Thompson [2]] Appl. No.: 123,498

[57] ABSTRACT [52] U.S. Cl ..74/6, 74/405 Starter gearing f the positive hift dent type Over [51] Int. Cl ..F02n 15/06 running clutch is shown herein In order to provide [58] Fleld of Search ..74/405, 6, 7 R, 7 A, 7 B maximum Service life with a minimum of wear the drive is provided with means forming a low friction [56] References cued substantially axially solid connection between the UNn-ED STATES PATENTS pinion and the starter gearing sleeve which interconnects the starter gearing with the rotary power shaft. 3,181,375 5/1965 Sabatini ..74/6 3,181,673 5/1965 Poliseo ..74/6 6 Claims, 1 Drawing Figure PATENTEUFEB 6 ms 3.714.834

50 52 54 a zzzo 18 a0 INVENIIOR. I

James .100 WITNESS.

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AT TORNEY ENGINE STARTING GEARING BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of starter gearing in general and in particular to that portion of the field of starter gearing which relates to positive shift dentil type overrunning clutch starter gearing.

2. Description of the Prior Art Clutches of the general type described hereinabove are well known in the art but the art teaches that such drives require rather complicated mechanism to separate the dentils of the overrunning clutch. An example of such a drive is illustrated in my earlier U.S. Pat. No. 3,263,509, assigned to the assignee hereof. Such mechanism as illustrated in the above-noted Letters Patent renders these drives suitable only for large engine installations, primarily large volume displacement diesel engines. It is, therefore, an object of the present invention to provide such a drive which is suitable for smaller engine installations. For the purposes of this application, small engine installations are those requiring less than about 70 lb. ft. of steady state torque during cranking. Such a drive must be low in cost and economical in service and must further provide long service life. By simply removing the complicated dentil separation mechanism and reducing the drive in size, a drive which generally meets the above described objectives may be obtained. However, such starter gearing suffers from a major defect. Simple reduction in size and elimination of parts results in a drive which is initially very reliable, but which eventually (within as little as one-fifth of its expected life) begins to suffer an impositiveness in engagement with the engine to be started. Examination of such drives has shown that a tooth abutment between the pinion gear and the gear of the engine to be started will prevent engagement of the drive and will also allow sufficient axial movement of the shifting mechanism for the starter motor contacts to be closed thereby causing the power shaft to rotate. Such action occuring without the interengagement of the pinion and the ring gear of the engine to be started results in a tooth milling, either of the ring gear or of the pinion, which thereafter requires expensive and time consuming replacement. It is, therefore, an object of the present invention to provide an economical reliable engine starter gearing having good torque transmitting characteristics and which has a long service life.

SUMMARY OF THE INVENTION In order to achieve the objectives of the present invention, the starter gearing according to the present invention is provided with a dentil type overrunning clutch which assures high torque transmitting capability and is further provided with thrust bearing means interconnecting the pinion gear and the starter gearing sleeve which couples the starter gearing to the rotary power shaft. By providing an intermediate low friction member, or washer, between a high speed rotating pinion and a comparatively low speed rotating body (the sleeve) the amount of rotary energy being transmitted from the pinion to the sleeve may be minimized.

BRIEF DESCRIPTION OF THE DRAWING The drawing shows, in a single FIGURE, starter gearing according to the present invention. The drawing depicts starter gearing according to the present invention in a partial elevational, partial sectional, -partially broken away FIGURE.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, there is illustrated starter gearing for an engine generally designated by the numeral 10, mounted on a power shaft 12 of a starter motor (not shown). The drive includes an axially extending sleeve 14 connected to shaft 12 by helical splines 16 so as to be axially movable relative to the shaft 12. The external surface of the forward or right hand extremity of the sleeve has helical splines 18 formed thereupon. A driving clutch member 20 is threaded and adapted for movement toward and away from a gear 22 of the engine to be started. For convenience, the sleeve 14 will be discussed and described as having a spline end which corresponds to the right hand extremity of the sleeve 14 and a yoke end which corresponds to the left hand end of the sleeve 14. A

pinion gear 26 is slidably journaled on bearing 63,

which in turn, is mounted on a second sleeve 28. Sleeve 28 is secured to sleeve 14 and is slidably supported on a reduced diameter portion of power shaft 12. The pinion gear 26 is adapted for movement into and out of engagement with the engine gear 22. An annular driven clutch member 30 is integrally formed with the pinion gear as the left most extension thereof as illustrated in the drawings. The driven clutch member is formed to provide an annular or circular recess 32 radially inwardly of the clutch member having its inner, or leftward, extremity defined by the end of sleeve l4'and its outer, or rightward, extremity defined by a shoulder on the pinion member 26 axially spaced from he end of sleeve 14.

The opposing or adjacent faces of the clutch members 20 and 30 are provided with complementary mutually engageable included torque transmitting dentil teeth 34 and 36, respectively. The dentils are of the saw tooth variety and provide a one-way overrunning clutch connection.

A barrel shaped housing 38, having a closed end and an open end, is slidably supported at its closed end 40 on the external surface of sleeve 14. A lock ring 42 is seated in a notch adjacent the closed end of the housing and establishes a left most extreme position for the barrel housing 38. A second lock ring 44 is seated in a notch adjacent the open end of the housing and has sufficient radial length to engage driven clutch member 30 to thereby confine the clutch elements within the housing cavity. The sleeve 14 is provided with a radial shoulder 46 intermediate its extremities to provide an abutment for a disc or washer means 48 slidably journaled on the sleeve 14. A resiliently yieldable cylinder 50, preferably of an elastically deformable material such as rubber, is compressively confined between the closed housing end 40 and the washer means 48. A resilient spring member 52 is compressively confined between the washer means 48 and the driving clutch member 20 to provide a biasing force urging the clutches in an engaged position.

Means for moving the starter gearing assembly toward or away from the engine gear 22 may comprise the conventional solenoid, air or hydraulic cylinder actuated lever, not illustrated, connected to the shift collar 54 which is coupled to the closed end 40 of barrel housing 38 by resilient means in the form of compressively confined spring 56. A stop ring 58 limits the leftward movement of shift ring 54 under the influence of spring 56 and thus defines the yoke end of sleeve 14,

A low friction thrust washer 60 is positioned within cavity or recess 32 so as to provide an axially substantially solid connection between sleeve 14 and pinion 26 while providing a low friction rotational interface therebetween. Thus, the interrelationship between the sleeve 14, thrust washer 60, pinion 26, and stop means 44 is operative to provide an axially substantially solid interconnection while the interrelationship of washer means 48, cylinder 50 and the closed end 40 of barrel housing 38 establishes an axially substantially constant position of the barrel housing 38 relative to the sleeve 14.

In operation, when it is desired to crank the engine, the starter gearing assembly is shifted to the right via positioning mechanism connected to collar 54 and along the power shaft 12 so that pinion gear 26 engages engine starter gear 22. Shaft 12 is rotated by a starting motor and transmits torque through splines 16 to sleeve 14, from helical splines 18 to the driving clutch 20, driven clutch 30, pinion gear 26 to the engine gear 22. As the engine fires and becomes self operating, engine gear 22 will now drive pinion 26 at a speed greater than that of the shaft 12. Clutch teeth 34 and 36 will slip so that the starting motor is not driven at high engine speed. This will result in the driven clutch member 30 forcing the driving clutch member 20 leftward along helical splines 18 against the compression of resilient means 52.

In the event that the initial rightward motion of the starter gearing results in a tooth abutment between pinion gear 26 and engine 22, the shift ring 54 will continue to travel rightward further compressing spring 56. At some point approximately equivalent to the full rightward movement, the starter motor contacts will be closed and the motor will begin to rotate shaft 12. This in turn will have the effect of rotating the starter gearing and the former tooth abutment should be eliminated. The drive will then advance under the compression energy of spring 56 and normal cranking can resume. in starter drives of the described type, which did not include any means for establishing a substantially axially solid connection between the pinion and the coupling sleeve, there tended to be a rightward movement of the barrel housing 38 while the pinion 26 and clutch members 20 and 30 tended to remain axially stationary relative to engine gear 22. This is believed to have resulted from the compression of both springs 52 and 56 and the fact that the stiffer spring 56 reacted more rapidly to the elimination of the abutment. This permitted the rotation of power shaft 12 to reach such high rotational energies that pinion ring gear milling of teeth occurred. However, with the starter gearing according to the present invention, all energy stored through compression of spring 56 is available to directly force pinion gear 26 into meshing engagement with the teeth of engine gear 22, thus preserving the integrity of the instant starter gearing while maintaining the reliability thereof.

The starter gearing mechanism, according to the present invention, accomplishes all of the normal functions of impact cushioning, overrunning, torque transmission, and in addition, eliminates impositive engagement of the pinion gear with the starter gear of the engine immediately following a tooth abutment situation. Manufacturing is readily accomplished as the annular recess 32 is a simple cylindrical configuration and thrust washer 60 may be any suitable material which readily provides low friction surfaces for interengagement with sleeve 14 and pinion 26.

lclaim:

1. Engine starter gearing comprising:

a power shaft;

a sleeve slidably secured to said shaft, said sleeve having external helical splines formed on one end thereof;

a pinion gear slidably journaled for axial movement relative to said shaft adapted for movement into and out of engagement with a gear of the engine to v be started;

an annular driven clutch member secured to said pinion gear for movement therewith and forming a circular recess radially inwardly of said driven clutch member;

said recess being defined by the radially extending end of the splined end of said sleeve, said driven clutch member and a shoulder portion of the pinion gear; driving clutch member having internal helical splines slidably mounted on said sleeve member with said internal helical splines in mating engagement with said sleeve external helical splines; said driving and driven clutch members having complementary mutually engageable inclined torque transmitting teeth for transmitting torque therebetween in one direction of relative rotation; a barrel housing having an open end and a closed end, slidably supported on said sleeve, said open end partially encompassing said clutch member; containment means within said housing adjacent the open end thereof adapted for engagement with the driven clutch member for confining said clutch member within said. housing; resilient means within said housing abutting said driving clutch member and biasing said clutch members into the engaged position; and low friction thrust bearing within said circular recess having a pair of spaced end faces, one of said faces in abutting relationship with said pinion and the other of said faces in abutting relationship with the end of said sleeve at least one of said pair of faces providing a low friction surface substantially perpendicular to the axis of said power shaft.

2. The starter gearing as claimed in claim 1 wherein said low friction surface abuts the end of said sleeve.

3. The starter gearing as claimed in claim 2 wherein the surface of said low friction thrust bearing abutting said pinion is substantially perpendicular to the axis of said power shaft.

4. Engine starting gearing comprising:

a power shaft having an axis of rotation;

a sleeve slidably secured to said shaft, said sleeve having a yoke end and a spline end and including external helical splines on said spline end;

a shifting ring intermediate the ends of said sleeve;

first stop means defining the extreme yoke end position of said shifting ring;

a pinion gear slidably journaled for axial movement relative to said power shaft adapted for movement into and out of engagement with a gear of the engine to be started;

an annular driven clutch member connected to said pinion gear for movement therewith and forming a circular recess radially inwardly of said driven clutch member; said recess being defined on one side of the spline end of said sleeve;

a driving clutch member having internal helical splines slidably mounted on said sleeve member with said internal helical splines in mating engagement with said sleeve external helical splines;

said driving and driven clutch members having complementary mutually engageable inclined torque transmitting teeth for transmitting torque therebetween in one direction of relative rotation;

a barrel housing having an open end and a closed end supported on said sleeve, said open end spatially encompassing said clutch members;

second stop means operatively associated with said sleeve for confining the closed end of said barrel thereby establishing a normal axial position of said barrel relative to said sleeve; resilient means compressively confined between said barrel and said shifting ring operative to bias said shaft ring towards said first stop means;

containment means within housing adjacent the open end thereof adapted for engagement with said driven clutch member for confining said clutch member within said housing;

second resilient means with said housing abutting said driving clutch member and biasing said clutch members into engagement; and

a low friction washer located within, and substantially filling, said circular recess to provide a low friction substantially axially solid connection between said sleeve and said pinion gear.

5. The starter gearing as claimed in claim 4 wherein said low friction washer provides a low friction surface in contact with the spline end of said sleeve.

6. The starter gearing as claimed in claim 4 wherein said low friction washer provides a low friction surface in contact with the pinion gear. 

1. Engine starter gearing comprising: a power shaft; a sleeve slidably secured to said shaft, said sleeve having external helical splines formed on one end thereof; a pinion gear slidably journaled for axial movement relative to said shaft adapted for movement into and out of engagement with a gear of the engine to be started; an annular driven clutch member secured to said pinion gear for movement therewith and forming a circular recess radially inwardly of said driven clutch member; said recess being defined by the radially extending end of the splined end of said sleeve, said driven clutch member and a shoulDer portion of the pinion gear; a driving clutch member having internal helical splines slidably mounted on said sleeve member with said internal helical splines in mating engagement with said sleeve external helical splines; said driving and driven clutch members having complementary mutually engageable inclined torque transmitting teeth for transmitting torque therebetween in one direction of relative rotation; a barrel housing having an open end and a closed end, slidably supported on said sleeve, said open end partially encompassing said clutch member; containment means within said housing adjacent the open end thereof adapted for engagement with the driven clutch member for confining said clutch member within said housing; resilient means within said housing abutting said driving clutch member and biasing said clutch members into the engaged position; and a low friction thrust bearing within said circular recess having a pair of spaced end faces, one of said faces in abutting relationship with said pinion and the other of said faces in abutting relationship with the end of said sleeve at least one of said pair of faces providing a low friction surface substantially perpendicular to the axis of said power shaft.
 1. Engine starter gearing comprising: a power shaft; a sleeve slidably secured to said shaft, said sleeve having external helical splines formed on one end thereof; a pinion gear slidably journaled for axial movement relative to said shaft adapted for movement into and out of engagement with a gear of the engine to be started; an annular driven clutch member secured to said pinion gear for movement therewith and forming a circular recess radially inwardly of said driven clutch member; said recess being defined by the radially extending end of the splined end of said sleeve, said driven clutch member and a shoulDer portion of the pinion gear; a driving clutch member having internal helical splines slidably mounted on said sleeve member with said internal helical splines in mating engagement with said sleeve external helical splines; said driving and driven clutch members having complementary mutually engageable inclined torque transmitting teeth for transmitting torque therebetween in one direction of relative rotation; a barrel housing having an open end and a closed end, slidably supported on said sleeve, said open end partially encompassing said clutch member; containment means within said housing adjacent the open end thereof adapted for engagement with the driven clutch member for confining said clutch member within said housing; resilient means within said housing abutting said driving clutch member and biasing said clutch members into the engaged position; and a low friction thrust bearing within said circular recess having a pair of spaced end faces, one of said faces in abutting relationship with said pinion and the other of said faces in abutting relationship with the end of said sleeve at least one of said pair of faces providing a low friction surface substantially perpendicular to the axis of said power shaft.
 2. The starter gearing as claimed in claim 1 wherein said low friction surface abuts the end of said sleeve.
 3. The starter gearing as claimed in claim 2 wherein the surface of said low friction thrust bearing abutting said pinion is substantially perpendicular to the axis of said power shaft.
 4. Engine starting gearing comprising: a power shaft having an axis of rotation; a sleeve slidably secured to said shaft, said sleeve having a yoke end and a spline end and including external helical splines on said spline end; a shifting ring intermediate the ends of said sleeve; first stop means defining the extreme yoke end position of said shifting ring; a pinion gear slidably journaled for axial movement relative to said power shaft adapted for movement into and out of engagement with a gear of the engine to be started; an annular driven clutch member connected to said pinion gear for movement therewith and forming a circular recess radially inwardly of said driven clutch member; said recess being defined on one side of the spline end of said sleeve; a driving clutch member having internal helical splines slidably mounted on said sleeve member with said internal helical splines in mating engagement with said sleeve external helical splines; said driving and driven clutch members having complementary mutually engageable inclined torque transmitting teeth for transmitting torque therebetween in one direction of relative rotation; a barrel housing having an open end and a closed end supported on said sleeve, said open end spatially encompassing said clutch members; second stop means operatively associated with said sleeve for confining the closed end of said barrel thereby establishing a normal axial position of said barrel relative to said sleeve; resilient means compressively confined between said barrel and said shifting ring operative to bias said shaft ring towards said first stop means; containment means within housing adjacent the open end thereof adapted for engagement with said driven clutch member for confining said clutch member within said housing; second resilient means with said housing abutting said driving clutch member and biasing said clutch members into engagement; and a low friction washer located within, and substantially filling, said circular recess to provide a low friction substantially axially solid connection between said sleeve and said pinion gear.
 5. The starter gearing as claimed in claim 4 wherein said low friction washer provides a low friction surface in contact with the spline end of said sleeve. 